SPE Library

The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.

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Conference Proceedings

FUNCTIONALIZED POLYETHYLENE AS PI COUPLING AGENT FOR BETTER DISPERSION OF EXFOLIATED GRAPHENE NANOPLATELETS IN HIGH DENSITY POLYETHYLENE MATRIX

Xian Jiang, Lawrence Drzal, May 2011

Previous work shows exfoliated graphene nanoplatelets (GNP) do not disperse well within high density polyethylene (HDPE) matrix which results in poor enhancement of conductive and mechanical properties. To improve the dispersion of GNP in HDPE, functionalized polyethylene (PE-g-Py) which is capable of electron interaction with the basal plane of GNP has been synthesized as the pi coupling agent. Mechanical, electrical and morphological characterization of HDPE/GNP nanocomposites in the presence of PE-g-Py have demonstrated the efficiency of this pi coupling agent to promote the dispersion of GNP which leads to considerably improved mechanical property and significantly reduced electrical percolation threshold.

DEVELOPMENT AND CHARACTERIZATION OF ENVIRONMENTAL FRIENDLY OPEN-CELL ACOUSTIC FOAMS

Mosanenzadeh Ghaffari, Hani Naguib, Chul B Park, May 2011

Although polymeric open-cell foams provide adequate absorption at medium and high frequencies, they are, as the majority of absorbing materials, inefficient in the low frequency range. Through this study, open-cell polymeric foams were fabricated from Polypropylene (PP) and Polylactide (PLA) by a novel fabrication method combining particulate leaching technique and compression molding. Fabricated foams were compared with a sample of Polyurethane (PU) foam. The materials used in this study are either recyclable or biodegradable which is of great importance considering huge amount of foams used as acoustic absorbers in various industries

FABRICATION AND THERMO-MECHANICAL CHARACTERIZATION OF Fe-Ni NANOPARTICLES /NYLON 6 COMPOSITES

Mawa Mohamed, Anastasios Patsidis, Mona Abd El-Latif, Azza El-Maghraby, Hassan Farag, Kyriaki Kalaitzidou, May 2011

The focus of this study was to develop Fe40Ni60/Nylon 6 nanocomposites and investigate their mechanical and thermal characteristics in order to provide a new polymer nanocomposite for engineering applications. Nanocrystalline Fe40Ni60 nanoparticles were chemically synthesized. Chemical composition, crystallite and particle sizes were determined. Fe40Ni60/Nylon 6 nanocomposites were prepared in a two step process: First the nanoparticles were mixed with Nylon 6 pellets either manually or using the solution mixing technique. Then the composites were fabricated through extrusion and injection molding. Results indicated that the manually mixed 3 wt% nanocomposite has higher storage modulus but lower impact strength than pure Nylon.

IN SITU OBSERVATION OF POLYSTYRENE FOAMING PROCESSES WITH CARBON DIOXIDE-NITROGEN GAS BLENDS

Anson Wong, Lun Howe Mark, Mohammad Hasan, Chul B. Park, May 2011

Carbon dioxide (CO2) and nitrogen (N2) are environmental-friendly blowing agents, but they pose various technical challenges to plastic foaming industries in producing high quality foams with uniform cell morphologies. Previous studies demonstrated improved foam morphologies when CO2/N2 blends were used, but the fundamental mechanisms of such foaming processes are not thoroughly understood. This study examines the foaming behavior of polystyrene (PS) blown with CO2/N2 blends by observing their foaming processes in situ.

INFLUENCE OF CROSSLINKING ON THE FOAMING BEHAVIOR OF ETHYLENE-VINYL ACETATE (EVA) USING CARBON DIOXIDE AS THE PHYSICAL BLOWING AGENT

Nan Chen, Ali Rizvi, Hui Wang, Chul B. Park, May 2011

This paper investigates the foaming behavior of Ethyl-vinyl acetate (EVA). A foaming chamber was designed to prepare foam samples using carbon dioxide as the physical blowing agent. The amount of crosslinking agent used in preparing the crosslinked EVA was correlated with the foam morphology. It was found that an optimum degree of crosslinking lead to high quality EVA foams with high expansion ratios. Extensional viscosity data were measured to describe the observed phenomena.

ACOUSTIC BEHAVIOR OF PERFORATED EXPANDED POLYPROPYLENE FOAM

Kamleshkumar Majithiya, Chul B. Park, Hani Naguib, May 2011

This study shows the acoustic behavior of perforated closed cell expanded polypropylene (EPP) bead foam structures to develop new application for EPP as an acoustic material. The closed cell EPP foam structure was perforated using mechanical perforation technique by drilling holes to make it open-celled foam. The perforated EPP foam was characterized for sound absorption. It is optimized by the selecting proper perforation ratio, which is governed by pore size and spacing between the adjacent two pores. The results obtained shows that EPP is a potential material for sound absorption application.

IMPROVEMENT OF THE STABILITY OF POLYMER BONDED RARE-EARTH-MAGNETS DURING THE INJECTION MOLDING PROCESS

Aleksander Gardocki, May 2011

Polymer Bonded Magnets can be cost effectively produced by injection molding of polymers with magnetic fillers. Rare-Earth-fillers (RE) like NdFeB or SmCo in comparison with other permanent magnetic fillers have remarkably higher magnetic properties. Nevertheless they are very reactive and oxygen susceptible which leads to polymer degradation and filler oxidation during the processing. This paper deals with two different methods of resolution to improve the thermal and thermo-oxidative stability of rare earth filled polymers during processing: powder coating and processing under inert atmosphere.

STRAIN LOCALIZATION AND RATE SENSITIVITY OF GLASSY POLYMERS UNDER SHEAR DEFORMATION

Jared Archer, Alan Lesser, May 2011

Shear deformation is used to investigate strain localization and rate sensitivity in glassy polymers using novel experimental techniques. The dynamic mechanical analysis of a series of acrylate-based polymers is used to relate molecular architecture to observed deformation trends. Narrow distributions of relaxation times associated with the beta relaxation correlate with higher levels of strain relaxation. The proximity of the test temperature to the temperature of the beta relaxation appears to strongly affect the rate sensitivity in PMMA. Physical aging is also shown to increase localization at low strain rates.

THE EFFECT OF TESTING PARAMETERS ON THE FUNCTIONAL IMPACT RESISTANCE OF UPVC COMMERCIAL PRODUCTS

Liam Driscoll, Joshua Anthony, Akshay Agarwal, May 2011

The testing of plastics has become decidedly different and as technology improves, it is necessary to evaluate the accuracy of results based on testing methods, particularly when functional durability is critical. The research discussed in this paper focuses on the effect of changing test parameters in relation to the falling dart impact test, more commonly referred to as the Gardner impact test (ASTM D5420). The drop weight protocol accommodates real geometries and reflects environmental conditions including temperature and percent relative humidity, as well as end-use impacting speeds but is affected by tup weight, probe diameter, and support ring.

PRELIMINARY RESULTS FOR INJECTION MOLDED SHORT GLASS FIBER THERMOPLASTIC COMPOSITES WITH A CIRCULAR FRONT

Syed Mazahir, Donald Baird, Peter Wapperom, Gregorio Garcia, May 2011

A two dimensional axisymmetric simulation for predicting the flow-induced orientation of glass fibers in injection molded composite parts is presented. The mass and momentum balance equations are discretized using Galerkin finite element method and the constitutive equation for fiber orientation is discretized using discontinuous Galerkin finite element method. Material parameters used in the model are determined using rheology and experimental fiber orientation is used for initial conditions. Simulation results are in close agreement with the trend seen in experimental data with still need for improving the simulation to capture the orientation in regions close to frontal flow and the walls.

MODELING ELASTOMERIC AND THERMOSET FOAMS: KINETICS, HEAT AND NUCLEATION

Nora Restrepo-Zapata, Tim Osswald, Juan Hernandez-Ortiz, May 2011

The curing reaction of an aliphatic epoxy resin and EPDM rubber is modeled from differential scanning calorimetry, generalizing a methodology proposed by Hernandez-Ortiz and Osswald. The kinetics is represented by Kamal-Sourour model with and without diffusion reaction control and was extracted using a non-linear regression method coupled with the heat and mass balance equations. The kinetic fitting methodology uses dynamic and isothermal differential scanning calorimetries allowing the differentiation of high and small peaks during the curing and diffusion reaction control regimens.

APPLICATION OF THE METHOD OF ELLIPSES FOR DETERMINING FIBER ORIENTATION IN LONG FIBER COMPOSITES

John Hofmann, Gregorio Garcia, Kevin Ortman, Donald Baird, May 2011

Fiber orientation within long glass fiber polypropylene composites in center-gated injection molded discs was determined at various percentages of flow. The results were compared directly to short fiber results for the same geometry. In addition, end-gated plaques were molded using the same short and long fiber materials for additional comparison. Results suggest that an area of high radial flow occurs for long fibers at low fill percentages during the filling process for end-gated plaques. Due to the increased length, long fibers have a large increase in flexibility and curvature within the injection molded system, complicating flow and prediction of orientation.

pH AND TIME DEPENDENT HYDROLYTIC DEGRADATION OF BIOPLASTICS FROM RENEWABLE MONOMERS

Matthew Rowe, Ersan Eylier, Keisha Walters, May 2011

Two renewable copolymers, poly(trimethylene malonate) (PTM) and poly(trimethylene itaconate) (PTI), have been produced with ester bonds incorporated into the polymer backbone to facilitate hydrolytic and/or enzymatic degradation. A hydrolytic degradation study of these renewable polymers in aqueous solutions adjusted to pH values is described. Final weight loss varied from 20 to 37 wt% for PTM and from 7 to 21 wt% for PTI as a function of aging time and initial solution pH. Degraded samples were characterized by FTIR, GPC, DSC, and TGA. PTI showed a slower degradation rate than PTM.

COMBINATIONAL EFFECTS OF MECHANICAL VIBRATION AND SHEAR ON THE CELL MORPHOLOGY OF MICROCELLULAR POLYMETHYL METHACRYLATE

Hai-Bin Zhao, Xiang-Fang Peng, Gang Liu, Nan Li, May 2011

In this paper, a novel electromagnetic dynamic foaming simulator was designed to investigate the combinational effects of shear and vibration on the morphology of microcellular polymethyl metacrylate (PMMA) samples by using supercritical carbon dioxide (ScCO2) as a blowing agent. Mechanical vibration induced by electromagnetic field was introduced into the foam process. Furthermore, in order to strengthen the shear effect, the rotor of the special designed simulator was machined to be whorled. It was shown that at a certain amplitude and frequency of vibration, the cell diameter of samples decreased and cell density increased.

DYNAMIC MECHANICAL PROPERTIES OF NOVEL POLYIMIDE/SUBTITUTED POLYANILINE-COPOLYMER-CLAY NANOCOMPOSITE FILMS

Jimmy Longun, Jude Iroh, May 2011

Novel polyimide/poly(N-ethyl-aniline-co-aniline-2-sulfonic acid-clay(SPNEAC-PI) nanocomposite films containing water soluble poly(N-ethyl-aniline-co-aniline-2-sulfonic acid-modified-clay (SPNEAC) have been successfully synthesized. The Dynamic Mechanical Spectrometry (DMS) results show decreasing Tg of the nanocomposite films with increasing SPNEAC loading. The area under the ñ-transition curve which is correlated with damping and impact energy increases with increasing SPNEAC loading. A 5wt% addition of SPNEAC improved damping of neat-PI films by 137%. SEM micrographs of the nanocomposite films showed an open cross-sectional morphology.

INFLUENCE OF SCREW CONFIGURATION AND MIXING CONDITIONS IN TWIN-SCREW EXTRUSION ON DISPERSION OF MWNT IN PCL COMPOSITES

Tobias Villmow, Bernd Kretzschmar, Petra Potschke, May 2011

To produce electrically conductive or electrostatic dissipative polymer composites containing carbon nanotubes (CNT) melt processing is the favored route. As electrical properties are desired at low filler fractions, a high degree of dispersion is required in order to benefit from the intrinsic CNT properties. This study discusses the influence of screw configuration, rotation speed, and throughput on the residence time and specific mechanical energy (SME) and the resulting macroscopic CNT dispersion in polycaprolactone (PCL) based masterbatches containing 7.5 wt.% multi-walled carbon nanotubes (MWNT) using an intermeshing co-rotating twin-screw extruder Berstorff ZE25. From the best masterbatch a dilution set was performed.

AUTOCLAVABILITY OF HIGH HEAT POLYCARBONATE RESINS FOR HEALTHCARE APPLICATIONS

Srinivas Siripurapu, Xiaoyu Sun, Scott Davis, John McCann, May 2011

Medical applications in healthcare market most often require multiple use or reuse of the instrument. Autoclave sterilization is one of the most common methods to effectively clean the instrument before reuse. To understand the capability of newly developed high heat Lexan* XHT resins in autoclave applications, mechanical property retention including tensile, flexural and practical impact properties were evaluated after multiple autoclave cycles at both 120?øC and 134?øC. These new class of high heat Polycarbonates offer better performance in comparison to conventional polycarbonates at high sterilization temperatures.

COMPARISON OF CARBON NANOTUBES AND CARBON NANOFIBERS BASED NANOCOMPOSITES PREPARED WITH AID OF HIGH POWER ULTRASOUND

Rishi Kumar, Avraam Isayev, May 2011

The unique morphology and strong inter-tube attraction among CNTs and CNFs makes the dispersion of CNTs and CNFs a big challenge and hence limits their effective use. The comparison of reinforcement efficiency of CNFs and MWNTs in PEI was studied. Ultrasound assisted single and twin screw extruder was used to prepare PEI/CNFs and PEI/MWNTs nanocomposites respectively. The effect of ultrasound on electrical, rheological, morphological and mechanical properties of polyetherimide filled with 1-10wt% of MWNTs and 2-20wt% of CNFs was studied. Ultrasonic treatment caused a reduction in electrical percolation threshold value with a permanent increase of viscosity of treated samples.

FIBER BREAKAGE CALCULATION FOR INJECTION MOLDED LONG FIBER COMPOSITES

Xiaoshi Jin, Jin Wang, May 2011

The Phelps-Tucker fiber breakage model has been implemented along with fiber orientation models in Autodesk Moldflow Insight to predict fiber length attrition during injection-molding process. The fiber length breakage model is based on the buckling criterion for hydrodynamic force determined by Dinh-Armstrong model, and probability distribution of the length breakage which parameters can be adjusted to match fiber length measurement. A set of measurement data has been used to validate the fiber breakage model implementation, and it has been extended to 3D simulation for more complicated geometries to predict the fiber length distribution in practical applications.

INTERRELATION BETWEEN MELT PROCESSING CONDITIONS, FORMULATION AND PROPERTIES OF POLYPROPYLENE / SHORT FLAX AND HEMP FIBER COMPOSITES

Mihaela Mihai, Johanne Denault, Christian Belanger, May 2011

This work investigates the effect of extrusion parameters and formulation on the properties of polypropylene / short flax fiber composites. The parameters that were varied during the twin-screw extrusion process were screw configuration, screw rate, extrusion temperature and flow rate. The effect of the location of the feeding zone of flax fibers is also considered. Concerning the composite formulation, the effect of flax content, presence of coupling agent and of a reactive additive on composite properties are analyzed. The materials were characterized in terms of morphological characteristics, rheological, thermal and mechanical properties.